The History of Petrochemical Transportation
Because of the wide diversity of locations where oil is harvested from earths"" underground reservoirs, it is necessary to transport the crude oil from a land or sea-based location to many sites across the globe for refinement. History books have recorded massive spillage of crude and catastrophic ecological damage during this transportation phase because of hull failure of the vessel transporting the crude. While oil spill prevention is the primary purpose of this invention, the invention contemplates the prevention of spills of various types of liquids and gasses, primarily in the petrochemical industry.
Currently Used Technology
Currently, only one transport process is being considered to significantly lower the risk of ecological damage resulting from the breach in the hull integrity of petrochemical transport vehicles: The Double Hull. Oil tankers built now and in the future are required by the Oil Pollution Act of 1990 (OPA ""90) to use double hulled construction to reduce the risk of oil spills due to grounding and collision, and the resulting adverse impact on the environment. Although the use of double hulls is a step in the right direction, it does not fully eliminate the likelihood of oil spills since the inner hull can still be penetrated in major accidents. Major oil spills, such as the 1989 Exxon Valdez oil tanker spill at Bligh Reef in Prince William Sound, Alaska, can have devastating impacts on the environment, and the cost of oil recovery and restoration of the environment can be extremely high. Although the double hull is currently perceived by the public and political figures as the most xe2x80x9cpolitically correctxe2x80x9d solution to the problem, after lengthy review of the options available, the double-hull concept is flawed and still capable of failure for the same reasons as the single hull. Even with the destruction of the entire remaining existing fleet of tankers, barges, and intermediate vessels and the expenditure of billions of dollars for the construction of The Double-Hull vessels, it is a fact that the Double-Hull vessel is still capable of being pierced or crushed by an incoming object when the force of that object exceeds the strength of the hulls. The Double-hull proponents merely hope that two hulls are enough. Recent history reaffirms that even two hulls are not enough. Even with this knowledge, the petrochemical industry, driven by legislative momentum, a massively powerful and financially well-endowed lobbying organization and the ongoing voluntary implementation of the Double-Hull vessels into the current transportation, there appears to be a feeling among the major petrochemical interests that the cost of correcting the flaw in the vessel construction problem would not find a receptive market. Once again, the industry appears to accept petrochemical cargo spillage as xe2x80x9canother risk of doing business.xe2x80x9d
Previous patents have struggled admittedly to only minimize the risk of hull breach with the use of various forms of bladders and reinforcement. Yet, each such patent admits that the loss of cargo would occur should both the bladder and its reinforcement be pierced during a hull breach.
This present invention allows the existing fleet of small, medium and large, single-hull and double-hull vessels that function as petrochemical transport vessels on various scales of magnitude, and VLCC (Very Large Crude Carriers) having single hulls to be converted and retrofitted to become more ecologically safe and physically predictable to unexpected hull pressures. Because of the custom nature of this invention, it is applicable to varying sizes of vessels.
Some of the Savings Expected By Using Existing Retrofitted Vessels
By using the existing retrofitted vessels with this invention:
1) Literally billions of dollars will be saved that would have been used in constructing the new and vastly more expensive replacement vessels. The money saved can be invested at a much higher rate of return yielding greater profits than would have been lost in the purchase of new vessels before the existing ones actually require replacement due to extinction or mechanical failures.
2) The additional fuel necessary to move the heavier mass of double-hull tankers will be conserved while payload volume of transported crude will be maintained. When this savings is considered for every journey of every vessel during the lifetime of the vessel until mandatory replacement, this is a major environmental and financial savings making worldwide utilization of this invention even more feasible.
3) The ship scrap debris created from the unnecessary destruction (usually sinking to the ocean floor) of the entire world fleet of tankers will lessen the environmental impact on the world""s refuse problem and the presence of sea-junk with its oxidation and ionic release into the sea.
4) And, the industry will have finally dealt with the actual petrochemical transport containment issues rather than just minimizing the risk but admitting the potential for failure of the other containment inventions. The potential damage to the environment as well as the financial outlay for clean-up or bio-remediation of spilled product is just too great to risk by not dealing with the actual problem at hand.
Positive Aspects of Utilizing This Invention
There are many positive reasons for utilization of this invention within the existing fleet of single-hull tankers that have been retrofitted with this present invention;
1) Improvement of existing vessels to deal with unexpected hull integrity problems;
2) Prevention of ecological tragedy that accompanies petrochemical spills;
3) Re-integration of vessel transport cell integrity following a hull breach where sea water enters the vessel;
4) Pre-Containment of Off-loaded crude;
5) Multiple-back-up system for off-loading of over-pressurized compartment contents;
6) Installation of invention with minimal time of vessel out of service;
7) Lower vessel hold maintenance costs;
8) Ability to change cargo type with more ease and safety from cross-contamination;
9) More safety to cleaning personnel of transport cells; and
10) Ability to protect off-loaded product from harm""s way.
An object of the present invention is to provide an improved cargo ship.
Another object of the present invention is to prevent hydrocarbon spills, or spills of other types of cargo, in the event the hull of a ship is breached.
An advantage of the present invention is a means for containing a hydrocarbon cargo, or other type of cargo, even after the hull or double hull of a ship is breached.
In the preferred embodiment of the invention, a method and apparatus are provided for containing cargo carried aboard a cargo carrier comprising a non-permeable, flexible bladder mounted within the carrier and in which the cargo is disposed and having an outlet port containing one or more check valves which allow the transported cargo to exit through such one or more check valves in the event the bladder is contacted by one or more objects which would otherwise cause the bladder to burst and spill the contents.
Therefore, in one embodiment the invention discloses an apparatus for containing cargo during a hull breach on a ship which comprises a non-permeable, flexible bladder mounted within the ship in which the cargo is disposed and a skeleton adjacent to the flexible bladder comprised of a plurality of relatively moveable elements for supporting the flexible bladder. The skeleton may be flexible and conformable to a shape of the flexible bladder. The plurality of relatively moveable elements forming the skeleton, in one embodiment, may comprise metallic links and/or metallic plates. There may be interconnecting metallic links mounted to the metallic plates.
This it should be appreciated that there has been described and illustrated herein new and improved methods and apparatus for preventing the spill of transported cargo aboard an oil tanker. However, the invention contemplates the use of such methods and apparatus for preventing the spills of various cargo materials on other means of transportation, for example, on barges, air craft which are used as tankers for refueling other aircraft while in flight, tanker trucks which are used to transport oil or other fluid cargos over the highway system, and the like.
The invention may include means for permitting flow from the bladder to compensate for a sudden increase in pressure in the bladder caused by a hull breach. In one embodiment, a pressure sensitive valve is secured to the non-permeable flexible bladder. One or more pressure sensitive valves is operable to open to release the cargo in response to a sudden increase in pressure in the non-permeable bladder due to the hull breach. The valve may close once the pressure is reduced to a normal value to seal the remaining cargo within the flexible bladder.
In one presently preferred embodiment, a plurality of tanks are provided wherein each tank may be much smaller than the flexible bladder. The pressure sensitive valve may then release the cargo into the plurality of tanks to take care of the overflow due to the hull breach. Preferably, each of the plurality of tanks is expandable so that storage is compact. A header may be provided for receiving the cargo from the pressure sensitive valve responsive to the hull breach. As the header is filled, the expandable tanks are filled with the excess.
In operation, the present invention provides methods for containing cargo during a hull breach on a ship. The method may comprise such steps as releasing cargo from a flexible container through a valve in response to increased pressure in the flexible container produced by the hull breach and directing the released cargo into the header on the ship. The method may comprise other steps such as filling at least one expandable tank, preferably with the released cargo in the header and may comprise releasing the at least one expandable tank over board after being filled with the released cargo. The method preferably includes supporting the flexible container with a plurality of support elements flexibly interconnected together.
In other words, an apparatus is provided for containing cargo during a hull breach on a ship which preferably comprises elements such as a non-permeable bladder mounted within the ship in which the cargo is disposed, a flexible support structure in surrounding relationship to the non-permeable bladder, and a valve secured to the bladder. The valve is preferably operable to open for releasing the cargo through the valve responsive to a hull breach. The flexible support structure may take on many forms such as a plurality of elements moveably linked together. In a preferred embodiment, at least one expandable tank may be provided which is placed in communication with the valve for filling in response to the hull breach. In one embodiment of the invention, the valve is responsively opened by an increase in pressure caused by the hull breach. A header pipe is secured to the valve for receiving the cargo and directing the cargo, if necessary, to a plurality of expandable tanks which are secured to the header for receiving the cargo therefrom.